Computer listing

 * Also changed shares and machines sidebars so they can be different
   upper menu options.
Samba4 machines edition
Machines can be now deleted
After component edition, we redirect the user to the component list

 * Also removed developing var_dump
Added delete share feature
Removed shares backup option from the shares list
Merge branch 'mjulian/frontend' of github.com:Zentyal/mmc into mjulian/frontend